sanding discs vs flapper discs and which brand ??

I use flap disks from Harbor Freight. They have two versions - I buy the zirconia ones that are 1$ more expensive - $9.99 for a three pack...

I prefer the Walter brand but they are expensive. In case you don't know the plastic on the edge can be machined off to expose the edge of the flaps when they get worn. You simply hold the spinning disc against the sharp edge of a metal work bench and peel away some of the plastic backing. This was demonstrated to me by a Walter rep. Randy

I haven't used a lot of them, but I noticed that the cheaper they are, the faster they fly apart. I guess that I can say that all I have used are Makita and HF. The HF wore out very quickly. The Makita lasted a lot longer.

A lot has to do with what you are doing with them, too, and how you load them. That is, how you press on the metal, and how hard, and what angle, how much metal you want to take off, and all that.

I will be following this thread, as it is time to go get some, and I want to get a decent deal.

Steve

There are _lots_ of disk types out there. Get a load of them (especially if your supplier offers bulk prices on mixed lots) and get a variety - then use what you liked.

In general, buy the best you can. They work better, they last longer, they work out cheaper long term. If you're using a grinder a lot, then your disk consumption will be significant and worth getting right.

Personally I use all of them from time to time, but most of all it's the flap disks. I only still use cutting disks and the hard grinding disks for working into corners where I need rigidity.

I don't use sanding disks though. An angle grinder is too fast for a simple flat disk and you get a lot of edge scoring that's work to take off afterwards. It's also too easy to overheat such a small area of abrasive. For sanding disks I might use a slower drill and some 3M non-round disks (rounded triangles) that don't have theis same edge-scoring problem.

I like the Hermes brand as an abrasive, especially their coated blue Zirconia. It's particularly good as sanding disks for wood, but it's good on a flap disk for metal too. They also use a plastic backing, which is softer if you run it into an edge, either accidentally or to shave a worn disk smaller. You can shave aluminium-backed disks down too (if you've only got one 40 grit left in the box and the shops are closed!) but it's a bit hazardous - it may catch and feed you a faceful of grinder.

I also like "Flexidisks", which I've only seen from Grayson. These are flap disks with half the number of flaps and a soft foam spacer between each one. They're expensive for general use, but they're good for convex compound curves as they don't wear flats by accident.

It's worth also investigating the extra-thin cutting disks, the paint-stripper plastic webs and the diamond disks for stone - they all have their uses at times.

I have found that the 3m disks purchased in bulk will save you money over the flapper disks. Especially if they are being used by hired help. If you have 7"or 9" sanders the disks can be purchased and the worn edges can be trimmed off for use on 4" tools. A tool is available for cutting down sanding disks for use on smaller tools.

OK, thanks for the input folks. Sort of confirms what my initial feeling had been (but I did not have much experience with them). I'll check out the 3M as well as some of the other comments here -- I'm getting quite fond of the little grinder - nice, light, lots of sparks !!

mikey